/
dynamo.go
123 lines (108 loc) · 3.21 KB
/
dynamo.go
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package iam
import (
"errors"
"fmt"
"os"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/awserr"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/dynamodb"
"github.com/aws/aws-sdk-go/service/dynamodb/dynamodbattribute"
)
type dynamoSession struct {
table string
awsSvc *session.Session
}
type dynamoUser struct {
Id string
EMail string
Name string
Disabled bool
Permissions []string
}
var EmptyResultError = errors.New("empty result")
func newDynamoSession(awssvc *session.Session) (*dynamoSession, error) {
var err error
if awssvc == nil {
awssvc, err = getAwsSession()
if err != nil {
return nil, fmt.Errorf("backend initialization failed: %w", err)
}
}
table := os.Getenv("DYNAMODB_TABLE")
if table == "" {
return nil, fmt.Errorf("DYNAMODB_TABLE must point to dynamodb table")
}
dynamo := &dynamoSession{
table: table,
awsSvc: awssvc,
}
return dynamo, nil
}
func getAwsSession() (*session.Session, error) {
region := os.Getenv("AWS_REGION")
if region == "" {
region = "eu-central-1"
}
conf := &aws.Config{
Region: aws.String(region),
}
return session.NewSession(conf)
}
func (dynctx *dynamoSession) getUser(uid string) (*dynamoUser, error) {
svc := dynamodb.New(dynctx.awsSvc)
table := dynctx.userTable()
dynamoItem, err := getDynamoItem(svc, table, uid)
if errors.Is(err, EmptyResultError) {
return nil, nil
} else if err != nil {
return nil, fmt.Errorf("failed to get record for user %q from dynamo table %q: %w", uid, table, err)
}
user := &dynamoUser{}
err = dynamodbattribute.UnmarshalMap(dynamoItem, &user)
if err != nil {
return nil, fmt.Errorf("failed to unmarshal user %q from table %q, %v", uid, table, err)
}
return user, nil
}
func getDynamoItem(svc *dynamodb.DynamoDB, table, id string) (map[string]*dynamodb.AttributeValue, error) {
input := &dynamodb.GetItemInput{
Key: map[string]*dynamodb.AttributeValue{
"Id": {
S: aws.String(id),
},
},
TableName: aws.String(table),
ConsistentRead: aws.Bool(true),
}
result, err := svc.GetItem(input)
if err != nil {
if aerr, ok := err.(awserr.Error); ok {
switch aerr.Code() {
case dynamodb.ErrCodeProvisionedThroughputExceededException:
return nil, fmt.Errorf("getitem error %v: %v",
dynamodb.ErrCodeProvisionedThroughputExceededException, aerr.Error())
case dynamodb.ErrCodeResourceNotFoundException:
return nil, fmt.Errorf("getitem error %v: %v",
dynamodb.ErrCodeResourceNotFoundException, aerr.Error())
case dynamodb.ErrCodeRequestLimitExceeded:
return nil, fmt.Errorf("getitem error %v: %v",
dynamodb.ErrCodeRequestLimitExceeded, aerr.Error())
case dynamodb.ErrCodeInternalServerError:
return nil, fmt.Errorf("getitem error %v: %v",
dynamodb.ErrCodeInternalServerError, aerr.Error())
default:
return nil, fmt.Errorf("getitem error (default): %v", aerr.Error())
}
}
return nil, fmt.Errorf("non-aws error: %v", err.Error())
}
if len(result.Item) == 0 {
return nil, fmt.Errorf("%q in %q: %w", id, table, EmptyResultError)
}
//fmt.Printf("GetItem result.Item: %v\n", result.Item)
return result.Item, nil
}
func (dynctx *dynamoSession) userTable() string {
return dynctx.table
}